Chaeles james dobbs



(No Mqdei.)

I o. J. DoBB-s. BRICK POR PAVING.

Patented Nov 29, 1887 I :Inl/edo?? l 1 (/arZe JJOZZS,

UNITED STATES PATENT OFFICE.

CHARLES JAMES DoEBs, E MIDDLESBEOUGH, COUNTY 0E YORK, ENGLAND.

BRICK `FOR PAVING.`

SPECIFICATION forming part of Letters Patent No. 374,118, dated November 29, 1887. Application filed December 23, 1886. Serial No. 222,35735. (No model.) Patented in England August 24, 1886, No. 10,829.

To all whom it may concern.'

' Be it known that I, CHARLES JAMES DOBBS, a citizen ofv England, residing at Middlesbrough, in the county of York, England, have invented a new and useful Improved Manufacture of Scoria Paving-Blocks, (for which I have obtained a patent in Great Britain, No.

-1o,s29,.dated August 24, 1886,) of which the following is a specification.

Paving-blocks made of blast-furnace scoria or slag have the disadvantage that by the chilling action of the mold in which they are cast the outer Skin assumes a very hard smooth texture that tends to slipperiness. According to my present invention I so manufacture such blocks that, instead of presenting the hard skin of the block as thel wearing-surface, I present a fractured surface of the block, which does not possess the glassy texture of the skin. For this purpose I form the molds for the blocks of sufficient size to make two or more blocks, and at the part of the mold corresponding to the division of the blocks into Separate lengths I form projecting ribs or fillets ou the bottom and sides ofthe mold, having a V shape, and I also place across the top of the mold a V- Shaped bar, so that on running in the liquid Slag a V-shaped groove is formed all round the block. After this has solidified and has been annealed in the usual manner, I subject the block to a blow, whereby it will be fractured at the point where the groove has been formed, and this more or less rough fractured surface I then use as the wearing-surface of the block.

' Figure l of the accompanying drawings shows a perspective View of a double slagblock cast with V-shaped grooves a a, asabove described; and Fig. 2 shows one-half of the block after being fractured across the grooved part, so as to produce a rough fractured surface, b, for the wearingsurface. Fig. 8shows a transverse section of the form of mold which I employ, by preference, for forming the grooved double block. Fig. 4 shows the same viewwith the mold opened. Fig. 5 shows a sectional front view of the mold.

The mold is formed of two separate parts, o d, hinged together at e, the part c being fixed to a turn-table, on the periphery of which a number of such molds-are xed. The two parts are held together in the closed position shown by the catchf, thus forming a rectangular box, in which are projecting V-shaped fillets 'g g g, and also a V-shaped bar, g', fixed to the part c and projecting across the open top ofthe mold. The one side,h, of the mold (shown in dotted lines in Figs. 3 and 4) is also formed on the part o and serves as the attachment to the turn-table, while the other side, h', and the bottom h2 are formed on the part d. The liquid slag being run into the mold and having solidified, the catch f is released, whereupon the part d of the mold, with the block in it, will drop into the position shown at Fig. 4, when the block will fall out, having the conguration shown in Fig. 1.

Although I prefer to cast the blocks with a Vgroove on all four sides, yet a single groove or two grooves on opposite sides may be sufficient. i

I am aware that tiles, wall-coping, and similar articles of terra-cotta have been molded with grooved division-lines, along which the article or articles can be Subsequently separated; but lthis I do not broadly claim, and my 75 invention differs therefrom iu that it embraces only a pavingblock of scoria having'a roughened wearing-surface produced by'i'racturing a double block of such material.

Having thus described the nature of my in- 8o vention and the best means I know for carrying the same into practical effect, I claim- As an improved article of manufacture, a scoria paving-block having a rougheued fractured wearing-surface, Substantially-as described.

In testimony whereof I have signed my name to this specification, in the presence oftwo subscribing witnesses, this 7th day of December, A. D. 1886.

CHARLES JAMES DOBBS. 

